Mice immune responses to Brucella abortus heat shock proteins. Use of baculovirus recombinant-expressing whole insect cells,purified Brucella abortus recombinant proteins,and a vaccinia virus recombinant as immunogens

Brucella abortus resists the microbicidal mechanisms of macrophages, and the expression of its heat shock proteins (HSPs) such as GroEL, GroES and HtrA may play a role in this resistance. Bacterial HSPs can be very immunogenic, inducing protective immunity in various types of bacterial infections. However, the significance of immune responses directed against B. abortus HSPs in the protection against brucellosis is currently unresolved. To elucidate the role of these proteins in protection against Brucella challenge, individual, divalent or trivalent baculovirus (BV) recombinants of B. abortus GroEL, GroES and/or HtrA were injected into BALB/c mice either as protein-expressing whole cells or as purified proteins. The preparations were given to mice in combination with Freund's or Ribi adjuvant, respectively. In addition, some mice were primed with a vaccinia virus-GroEL recombinant, followed by inoculation with purified GroEL-Ribi adjuvant combination. Antibodies were observed against B. abortus GroEL and HtrA, but not against GroES. Cellular immune response was demonstrated by observing significant IFN-gamma release by lymphocytes of mice immunized with the purified HtrA-Ribi adjuvant combination. However, none of the mice inoculated with individual, divalent or trivalent HSP-expressing cells combined with complete Freund's adjuvant or inoculated with purified B. abortus HSPs combined with Ribi adjuvant, were protected against challenge with B. abortus virulent strain 2308. Priming with vaccinia virus-GroEL recombinant and boosting with GroEL-Ribi combination did not induce protective immunity. Based on the results obtained, we suggest that although humoral and cell-mediated immune responses are induced, but protective immune response is not induced by B. abortus HSPs.     

猪O型口蹄疫病毒样颗粒的构建及鉴定

为开发猪O型口蹄疫病毒（FMDV）病毒样颗粒（VLPs）基因工程亚单位疫苗,试验参考GenBank中登录的FMDV毒株基因序列（登录号：JN998085）,设计针对VP1、VP2、VP3和VP4 4个基因片段的特异性引物,以O型FMDV O/MYA98/XJ/2010毒株的cDNA序列为模板,对目的基因进行PCR扩增;将获得的VP3、VP1和VP4、VP2基因片段分别插入2个杆状病毒供体质粒（pFastBacDual）的p10和pH双元启动子中,构建pFBD-VP3-VP1和pFBD-VP4-VP2 2个重组转座质粒;将验证正确的2个重组转座质粒分别转化含有穿梭载体（Bacmid）的大肠杆菌DH10Bac感受态细胞,获得2个重组杆粒rBacmid-VP3-VP1和rBacmid-VP4-VP2,经验证正确后,对其进行扩增和提取,将其分别转染Sf9贴壁昆虫细胞,构建2个重组杆状病毒rvAc-VP3-VP1和rvAc-VP4-VP2;2个重组杆状病毒共同感染悬浮培养的Sf9昆虫细胞,利用杆状病毒表达系统在昆虫细胞内对4个基因进行表达,目的蛋白通过间接免疫荧光试验（IFA）、SDS-PAGE、Western blotting及透射电镜（EM）进行检测。结果显示,本研究成功构建2株分别表达FMDV VP1、VP2、VP3和VP4 4个结构蛋白的重组杆状病毒;特异性抗体检测发现,4个蛋白VP1~VP4均成功表达,且具有良好的特异性反应;4个蛋白在Sf9昆虫细胞内能够完成自我组装,形成与天然病毒结构相似的VLPs,直径大小在25~30 nm。本研究利用共感染表达方式在Sf9昆虫细胞内成功制备出FMDV病毒颗粒,为开发高效安全的FMDV基因工程亚单位疫苗开辟了一条新思路。     

输卵管特异表达人溶菌酶基因重组禽腺联病毒的构建及鉴定

试验旨在利用杆状病毒表达系统制备输卵管特异表达人溶菌酶（hLYZ）的重组禽腺联病毒（recombinant avian adeno-associated virus,rAAAV）。参照已发表的hLYZ基因序列设计1对引物,PCR扩增hLYZ基因片段,亚克隆至含输卵管特异表达盒和禽腺联病毒（AAAV）两侧末端反向重复序列（inverted terminal repeat,ITR）的转移载体中,获得重组杆状病毒转移载体pFB-AIOVLYZ,将其转化到大肠杆菌DH10Bac感受态细胞中,经抗性和蓝白斑筛选,获得重组穿梭质粒rBacmid-AIOVLYZ,在脂质体介导下转染Sf9昆虫细胞,获得重组杆状病毒rBac-AIOVLYZ。将其与表达AAAV结构蛋白的重组杆状病毒rBac-VP及表达AAAV功能蛋白的重组杆状病毒rBac-Rep以感染复数（multiplicity of infection,MOI）为5感染Sf9昆虫细胞,72 h后收集细胞沉淀,并经滤膜过滤、氯仿抽提和PEG沉淀,即为rAAAV-OVLYZ。电镜结果显示,病毒粒子大小约为20 nm,形态结构与野生AAAV相似;PCR结果显示rAAAV含有目的基因;体外细胞表达试验说明rAAAV能介导hLYZ在输卵管细胞中的特异表达。结果表明,本研究利用杆状表达系统成功制备了输卵管特异表达hLYZ基因的rAAAV,为hLYZ的大量制备奠定了基础。     

Construction and Identification of Recombinant Avian Adeno-associated Virus Oviduct-specific Expressing Human Lysozyme Gene

In order to produce recombinant avian adeno-associated virus (rAAAV) oviduct-specific expressing human lysozyme (hLYZ) by the baculovirus expression system, one pair of primers was designed according to the published sequences for hLYZ, the hLYZ gene was amplified by PCR and cloned into baculovirus expression vector, which contained the oviduct-specific expression cassette and the inverted terminal repeats of avian adeno-associated virus (AAAV), the resulted plasmid was named as pFB-AIOVLYZ.Then the recombinant vector pFB-AIOVLYZ was transformed into E.coli DH10Bac, and the positive recombinant bacmid rBacmid-AIOVLYZ was screened according to the resistant and the blue-white plague screening,rBacmid-AIOVLYZ was transfected into the Sf9 insect cells by liposome. Once the cytopathic effect was found, the rBac-AIOVLYZ could be harvested.Sf9 insect cells cultured in suspension culture were infected with three recombinant baculoviruses, rBac-AIOVLYZ, rBac-VP and rBac-Rep, at an MOI of 5. 72 h later, Sf9 insect cells were collected, and recombinant viral particles rAAAV-OVLYZ were purified by filtration, chloroform extraction and PEG precipitation. Electron microscopy showed a typical morphologic feature of Parvoviridae family with virus particle size of about 20 nm. PCR results indicated that the target gene existed in the viral genome. The in vitro cell expression test showed that rAAAV could mediate the specific expression of hLYZ in oviduct cells. These results indicated that the rAAAV oviduct-specific expressing hLYZ was successfully prepared by baculovirus expression system, which laid the foundation for the preparation of hLYZ.     

鸡传染性贫血病毒VP1、VP2基因的表达及免疫原性研究

为探索鸡传染性贫血重组蛋白亚单位疫苗的可行性,将鸡传染性贫血病毒基因分别克隆到转移载体p Fast Bac HTA中,再将其分别转化DH10Bac感受态细胞得到相应的重组表达载体,转染昆虫细胞Sf21获得含有VP1、VP2基因的重组杆状病毒v Bac-VP1、v Bac-VP2,应用悬浮培养的Sf21细胞表达重组蛋白。SDS-PAGE及Western blotting结果证明,VP1、VP2基因在昆虫细胞中得到了表达,动物试验进一步证实,重组蛋白免疫SPF鸡可产生ELISA抗体,提示杆状病毒表达的VP1、VP2具有良好的免疫原性。     

新疆绵羊种布鲁氏菌HtrA基因与GroEL基因的克隆及其原核表达

根据已发表的牛流产型布鲁氏菌HtrA（High temperature requinnent A）基因、GroEL（热休克蛋白）基因设计特异性引物，从新疆绵羊种布鲁氏菌基因组中扩增出HtrA、GroEL基因片段，将HtrA、GroEL基因片段纯化后分别克隆到T载体上测序，结果表明新疆绵羊种布鲁氏菌HtrA基因片段长1542bp，编码513个氨基酸，与发表的牛种（B．abortus）、羊种（B．melitensis）、猪种（B．suis）的HtrA基因序列的同源性分别为99．68％、99．81％、99．55％。GroEL基因片段长1641bp，编码546个氨基酸，与B．melitensis、B．suis以及B．aborms GroEL基因的核苷酸序列同源性分别为99．88％、99．82％、99．88％。HtrA基因和GroEL基因与发表的B．abortus、B．melitensis、B．suis的HtrA基因和GroEL基因序列的具有很高的同源性。按正确的阅读框架分别将两基因片段定向克隆到表达载体pET．28a上，将重组质粒转化到大肠杆菌BL21菌株，经IPTG诱导表达，SDS-PAGE电泳和western blot分析表明，HtrA、GroEL基因能在大肠杆菌中成功表达，表达的蛋白分子量都约为60Ku，并能和布鲁氏菌免疫兔子产生的抗体发生特异性的结合。     

传染性支气管炎病毒非结构蛋白nsp5在真核细胞中的重组表达及鉴定

本文以嗜肾型鸡传染性支气管炎病毒(Infectious bronchitis virus,IBV)毒株的RNA为模板,通过RT-PCR扩增获得IBV非结构蛋白5(non-structural protein,nsp5)基因片段后,构建了杆状病毒重组质粒IBVnsp5-Bacmid。IBVnsp5-Bacmid转染Sf9细胞,获得nsp5重组杆状病毒,经(immunofluorescence assay,IFA)和Western blot检测到转染细胞表达的nsp5蛋白。进一步从感染的细胞中纯化重组蛋白,并用纯化的蛋白免疫小鼠制备了抗nsp5的多抗血清,该多抗血清可检测到IBV四川株SC021202感染的DF-1细胞中特异性的nsp5蛋白。结果表明IBV nsp5在Bac-to-Bac真核表达系统中获得了成功表达,而且具有良好的免疫原性和反应原性。     

狂犬病病毒磷蛋白在杆状病毒系统的表达及鉴定

为了建立狂犬病毒磷蛋白(phosphoprotein,P)的体外表达系统,本研究将RT-PCR扩增的狂犬病病毒ERA株P蛋白基因克隆于杆状病毒转移载体pFastBacHTA,构建重组质粒pFastBacHTA-P,并转染昆虫细胞Sf9包装形成重组杆状病毒。SDS-PAGE分析显示重组质粒pFastBacHTA-P转染的Sf9细胞中出现了分子量约为42 kDa的蛋白条带,Western blot证实分子量约为42 kDa的蛋白能与抗His的单克隆抗体发生特异性反应,间接免疫荧光(indirect immunofluorescence assay,IFA)分析进一步显示Sf9细胞表达的P蛋白与抗P蛋白单克隆抗体能特异性结合。这些实验证明,狂犬病病毒P蛋白不仅在Sf9细胞中获得表达,而且具有良好的免疫反应性。狂犬病病毒P蛋白杆状病毒表达体系的建立,为蛋白结构的解析和诊断试剂的研制奠定了基础。     

口蹄疫病毒P12X3C3D多基因编码蛋白在昆虫细胞中的表达与检测

利用杆状病毒表达系统构建了包含有口蹄疫病毒（FMDV）P12X3C3D多基因片段的重组杆状病毒。将该病毒感染Sf9细胞后，利用SDS—PAGE及夹心ELISA方法检测目的蛋白的表达。结果表明，重组杆状病毒能够表达FMDV目的蛋白，该表达产物能被FMDV阳性血清识别，具有一定的反应原性。     

Study on Expression and Immune Effect of F Protein of Newcastle Disease Virus Type Ⅶ in Insect Cell

This experiment was conducted to study the protein expression of F gene of Newcastle disease virus (NDV) type Ⅶ by baculovirus expression system.The F gene was amplified by RT-PCR and cloned into pFastBac HT A plasmid, and then the recombinant plasmid was transformed into DH10Bac competent cells to get the positive recombinant bacmid.After 72 h transfection of Sf9 cell with recombinant bacmid, the expression of interest protein was detected by indirect immunofluorescence assay (IFA), SDS-PAGE analysis and Western blotting. Serum antibody titers of immunized SPF chickens were determined by ELISA and the protective properties were determined by protection test. The results showed that F gene was expressed in Sf9 cells infected with the recombinant baculovirus. The expressed protein could induce high titer specific antibody against NDV. The protective rate of recombinant F protein group was 90%, which was significantly higher than that of the negative control group. These results laid a foundation for study on NDV subunit vaccine.     

基因Ⅶ型新城疫病毒F蛋白在昆虫细胞中的表达及免疫效力研究

本试验旨在利用杆状病毒表达系统对基因Ⅶ型新城疫病毒（NDV）F基因进行表达研究。RT-PCR扩增F基因,将其克隆到pFastBac HT A载体中,阳性重组质粒转化DH10Bac感受态细胞,PCR鉴定获得阳性克隆,碱裂解法提取阳性质粒,转染Sf9昆虫细胞,获得含F基因的重组杆状病毒质粒,重组病毒感染Sf9细胞72 h后,进行SDS-PAGE电泳、间接免疫荧光和Western blotting检测。免疫SPF鸡,间接ELISA测定抗体滴度,攻毒保护试验检测重组F蛋白保护性。结果显示,F蛋白在昆虫细胞中能够特异性表达,该蛋白诱导了高滴度的NDV特异性抗体,具有良好的免疫原性;重组F蛋白免疫组攻击保护率达到90%,明显高于阴性对照组。本研究结果为NDV新型亚单位疫苗的研究奠定了基础。     

传染性法氏囊病病毒VP2基因在昆虫细胞中的表达

本研究将鸡传染性法氏囊病病毒超强毒(very virulent infectious bursal disease virus,vvIBDV)JM-1/10株VP2基因克隆至pcDNA-3.1(+)启动子CMV之后,随后将CMV-VP2基因序列一同克隆入杆状病毒表达系统的质粒 pFastBac^TM Daul中构建了pFast-CMV-VP2。将pFast-CMV-VP2转化Escherichia coli DH10Bac感受态细胞,筛选出重组质粒Bacmid-CMV-VP2。用 Bacmid-CMV-VP2转染Sf9昆虫细胞,获得了重组杆状病毒vBac-CMV-VP2。将该重组杆状病毒转导BHK-21细胞,48~72 h后经间接免疫荧光试验(IFA)检测到VP2蛋白具有特异性荧光;样品经Western blotting分析,结果显示目的蛋白得到表达。结果表明,本试验制备的重组 vBac-CMV-VP2 既能在昆虫细胞中表达,也可在哺乳动物细胞中表达。     

猪瘟病毒石门株E2蛋白在杆状病毒系统中的表达

以杆状病毒Bac-to-Bac表达系统表达猪瘟病毒(CSFV)石门株的E2蛋白,将CSFV石门株的E2囊膜糖蛋白基因亚克隆到杆状病毒转移载体pFastBacHTA中,获得重组转移质粒pFastBacHTA-E2。转化大肠埃希菌DH10Bac感受态细胞,获得重组Bacmid质粒后转染Sf9昆虫细胞,获得重组病毒。传毒3代后对表达蛋白进行Western blot和间接免疫荧光试验检测。结果显示,E2蛋白获得高效表达,能被抗E2蛋白的单克隆抗体2B10和6×His-单克隆抗体特异性识别,表明CSFV石门株E2囊膜糖蛋白在Sf9昆虫细胞中得到成功表达,具有良好的抗原反应性。     

悬浮培养Sf21细胞高效表达牛γ-干扰素及其特性鉴定

本试验旨在研究重组牛γ-干扰素(rBovIFN-γ)在Sf21细胞中高效表达及其特性鉴定。利用逆转录—聚合酶链式反应(RT-PCR)技术从奶牛外周血淋巴细胞的总RNA中扩增出不含信号肽的BovIFN-γ基因片段。将其克隆到pFastBac^TMHTA中构建重组质粒pFastBac^TMHTA-BovIFN-γ。然后将重组质粒转化至DH10Bac感受态细胞获得重组穿梭质粒rBacmid-BovIFN-γ。转染Sf21昆虫细胞后获得重组杆状病毒rBac-BovIFN-γ,应用Sf21细胞悬浮培养技术大量表达rBovIFN-γ。利用Western blotting、质谱分析(MS)、抗病毒试验等对rBovIFN-γ进行鉴定。Western blotting分析显示,rBovIFN-γ具有良好的反应原性;MS分析表明,rBovIFN-γ的6个肽段序列与牛IFN-γ的氨基酸序列完全匹配,在蛋白质质谱数据库中搜索结果为牛IFN-γ;MDBK/VSV抗病毒试验显示,rBovIFN-γ具有很高的抗病毒活性,为1.05×10⁵ IU/mg。     

Sf9昆虫细胞悬浮培养工艺的研究

对Sf9昆虫细胞在不同培养基、培养基中是否添加血清及不同生物反应器中的培养工艺进行了研究,发现Sf9细胞在Sf900Ⅱ无血清培养基中生长比在添加10％小牛血清的Grace培养基中更好,在Sf900Ⅱ无血清培养基14 L搅拌式生物反应器分批培养细胞密度可达1.4×107/mL.过程生化特性分析表明,总氨基酸的消耗及主要代谢副产物特别是乳酸及游离氨的积累是培养后期细胞密度降低及活性下降的重要原因.本研究为Sf9细胞生物反应器培养工艺优化及利用昆虫杆状病毒蛋白表达系统高效表达重组蛋白生产亚单位疫苗奠定了良好基础.     

Expression and Identification of F Gene of Duck Newcastle Disease Virus in Insect Cells

In order to express the F protein of duck Newcastle disease virus (NDV) in insect cells,one pair of specific primers was designed according to the published genome sequences of duck NDV to amplify F gene by PCR,the amplified fragment was cloned into baculovirus expression vector pFastBac1.Then the recombinant vector pFastBac-F was transformed into E.coli DH10Bac competent cells,and the positive recombinant bacmid rBacmid-F was screened according to the resistance and blue-white plague screening.rBacmid-F was transfected into Sf9 insect cells by liposome,once the cytopathic effect was found,the rBac-F could be aquired.The results of Western blotting and indirect immunofluorescence test showed that the recombinant proteins could be recognized by positive serum,indicating that the protein had good reactiongenicity.These results suggested that F protein of duck NDV had been successfully expressed in insect cells,which laid the foundation for the prevention and control of duck Newcastle disease.     

鸭源新城疫病毒F基因在昆虫细胞中的表达和鉴定

为在昆虫细胞中表达鸭源新城疫病毒(NDV) F蛋白,本试验首先根据鸭源NDV F基因序列设计引物,PCR扩增出F基因,将其克隆至杆状病毒表达载体pFastBac1,获得重组转座载体pFastBac-F,将其转化到大肠杆菌DH10Bac感受态细胞中,经抗性和蓝白斑筛选,获得重组杆状病毒穿梭质粒rBacmid-F,在脂质体介导下转染Sf9昆虫细胞,获得重组杆状病毒rBac-F。Western blotting、间接免疫荧光试验结果均显示表达的重组蛋白能与鸭抗NDV阳性血清发生特异性反应,具有良好的反应原性。结果表明鸭源NDV F蛋白在昆虫细胞中获得了成功表达,为鸭新城疫的预防控制奠定了基础。     

H5亚型禽流感病毒样颗粒的构建及生物学活性鉴定

为构建H5亚型禽流感病毒(AIV)病毒样颗粒(VLPs),并鉴定其生物学活性,本研究通过杆状病毒/昆虫细胞表达系统,分别单独表达H5亚型AIV血凝素(HA)及共表达HA和基质蛋白(M1),并采用免疫组织化学法、SDS-PAGE、western blot和血凝试验等对重组蛋白进行鉴定。实验结果表明:透射电子显微镜观察结果显示,共表达HA和M1的重组蛋白可以形成VLPs,而单独表达HA未观察到VLPs;表达的重组蛋白HA和HA-M1均能够凝集鸡红细胞,血凝效价分别为1∶27和1∶28。结果显示该方法获得的AIV结构蛋白具有良好的生物学活性和抗原活性,从而为禽流感VLPs疫苗的研究提供依据。     

伪狂犬病病毒gE/gI基因在昆虫细胞中的表达及鉴定

为获得具有生物活性的伪狂犬病病毒(Pseudorabies virus,PRV)gE/gI蛋白,建立PRV抗体快速检测方法。将含有PRV gE、gI基因的质粒pFastBacdual-GP67-gE/gI转化至宿主菌,经位点特异性重组和蓝白斑筛选后获得重组杆粒rBacmid-gE/gI,转染Sf9细胞,获得重组杆状病毒。采用悬浮的Sf9细胞进行发酵并纯化产物,SDS-PAGE和Western blot分析镍柱纯化后的重组蛋白。结果显示,重组杆粒在4800 bp处克隆出预期大小的条带,表示重组杆粒构建成功。SDS-PAGE和Western blot表明,在50 ku和65 ku处出现预期大小的条带,能与PRV标准阳性血清特异性反应,不与PRV gE/gI缺失疫苗免疫血清反应。结果表明gE/gI重组蛋白具有良好的反应原性,为PRV抗体快速检测及区分PRV野毒感染和疫苗免疫奠定了基础。     

禽呼肠孤病毒σB和σC蛋白在昆虫细胞中的共表达

本研究旨在获得具有天然构象和活性良好的禽呼肠孤病毒（ARV）σB和σC蛋白,采用杆状病毒表达系统在昆虫细胞中共表达σB和σC蛋白,并对其活性进行鉴定。根据NCBI数据库中ARV σB和σC基因序列设计引物,将两个基因克隆至pFast-Dual载体,转化大肠杆菌DH10Bac感受态细胞,筛选获得重组穿梭杆粒。通过转染sf9细胞,筛选到含有σB和σC基因的重组病毒。将重组病毒感染sf9细胞,通过优化接毒量和收获时间等参数,确定最佳表达条件,在sf9细胞中高效共表达σB和σC蛋白。Western blotting和间接免疫荧光（IFA）检测结果表明,成功在sf9细胞中共表达了ARV σB和σC蛋白,并具有很好的生物学活性。本试验结果为开发鉴别诊断试剂以及ARV颗粒疫苗的研究奠定了基础。